Levoscoliosis — Scoliosis Curve Directions Explained

Medical experts and others interested in describing scoliosis use a number of terms and phrases to describe and communicate the features of this postural misalignment. Such terms address, for example, the area (i.e., cervical, thoracic, lumbar, etc.) of the spine in which the curve or curves are located, the cause of the scoliosis and/or how many total sideways curves a spine has.

Levoscoliosis and Dextroscoliosis

Another set of terms classifies scoliosis by the direction into which your spine curves. For curve direction information, two terms, which also serve as building blocks for more complex descriptions of individual patterns of scoliosis are used. The terms are: Levoscoliosis and dextroscoliosis.

As I said, the terms levoscoliosis and dextroscoliosis are often combined with additional terms that describe other aspects of scoliosis — such as the location of the curve. 

Keep in mind that levoscoliosis and dextroscoliosis refer to curve direction in relation to the midline of your body.

Let’s take a careful look at each term to get their meanings down pat, and enable you to discuss your or your child's scoliosis with skill.

Levoscoliosis refers to a spinal curvature that bows out to the patient's left. Levoscoliosises usually, but not always, occur in the lumbar spine. For example, the diagram above shows a thoracic levoscoliosis.

Remember, medical experts have a very specific way to define both levo and dextro-scoliosis, which is about where the spinal column migrates relative to the midline of the body. In people with a straight spine, the column is generally located at this ideal midline area.

When you first look at the accompanying image, it may seem to you that the curve is going to the right side. This may be because the patient is side bending to the right as a result of the bones of the spine having moved away from the midline and towards the left. Because the spinal bones are left of center, so to speak, the patient's well-aligned spinal balance is interrupted, and out of day in and day out posture and movement habits, the person tends to drop over, or side bend, to the right. In this way the patient finds the best possible support for upright posture, given the fact that they are dealing with a levoscoliosis.

But left unchecked, their muscles on either side of the levoscoliosis (plus others) may weaken and tighten, which then serves as a sort of glue that keeps the posture in a side bend. Over time, these muscle conditions may worsen, increasing both the degree of the levoscoliosis and the degree of the side bend.

So if you see the spine move to the left, as it does in this diagram and in the slide that follows, in diagnostic terms, it means the curve is going to the left.

To diagnose the direction of your lateral spinal curve, your doctor will likely determine the direction into which the spinal column deviates from the  (imaginary) midline of your body. If the spinal column devieates to the left, it's a levoscolosis.

A levoscoliosis is shown on a live body (rather than a diagram of the skeleton.) In this instance of levoscoliosis, the curve is lower down than in the previous image.

An idea circulating among experts and other interested people is that left thoracic curves tend to be associated with diseases, while right thoracic curves are more "normal." (This is according to a 1999 study published in Spine.)

While the researchers of the 1999 study did find an association between left thoracic curves and disease, it wasn't a very strong one. Instead of further tests on patients with left T-spine curves, or special treatment, the authors say that male gender and the age of scoliosis onset in girls are more important risk factors to watch.

They also say that every new case of scoliosis deserves an equally meticulous assessment, and that more sophisticated tests should be given based on the patient's entire clinical picture, not just the presence of a left thoracic curve.

If levoscoliosis is a lateral spinal curve to the left of the midline of the body, dextroscoliosis is the opposite. This term refers to a spinal column that bows out to the patient's right. In a dextroscoliosis, the body tends to side bend to the left.

Most of the time, a dextroscoliosis occurs in the thoracic spine.

A person's spine can have both a dextroscoliosis and levoscoliosis. In this image of an x-ray, the thoracic spine (top part) shows a dextroscoliosis, and the lumbar spine (bottom part) shows a levoscoliosis.

Source:

Goldberg C., Moore D., Fogarty E., Dowling F.Left thoracic curve patterns and their association with disease. Spine (Phila Pa 1976). June 1999. Accessed Feb 2016.http://www.ncbi.nlm.nih.gov/pubmed/10382250